Add docs hotfix

 ## Why is the change being made?

This change is made because our readthedocs is currently broken.

 ## What has changed to address the problem?

This change adds a requirements.txt file.

 ## How was this change tested?

This change was tested here: https://readthedocs.org/projects/ground-control-station/builds/10518429/

 ## Related documents, URLs, commits

requirements.txt

@@ -0,0 +1,3 @@
+mkdocs-git-revision-date-localized-plugin
+mkdocs-material
+markdown-include